For antiperspirant products, their efficacy can be measured using the procedure from the U.S. Food and Drug Administration, which is described in 21 CFR 350 and its subparts and in Guidelines for Effectiveness Testing of OTC Antiperspirant Drug Products (http:www.fda.gov/downloads/AboutFDA/CentersOffices/CDER/ucm106437.pdf). This method describes how to apply an antiperspirant to a test subject and have the test subject sit in a hot room to measure the level of perspiration. The level of perspiration reduction is compared to an area on the test subject where no antiperspirant was applied or a control formulation was applied.
This method requires an absorbent pad to be applied to a test area to collect perspiration. The absorbent pad in the test area is compared to the control area to determine the difference in the level of perspiration between the two areas.
One drawback to this method is that the absorbent pad is in direct contact with the area where the composition is applied to the skin. While traditional antiperspirants work by penetrating the pores and forming a plug thus not remaining on the surface of skin, other compositions that can be used to reduce perspiration, such as occlusives or film formers, work by forming a layer on skin. When the absorbent pad comes into contact with the composition, the absorbent pad may remove some or all of the composition. This leads to an inaccurate result for the test. It would be desirable to have a test method that does not interfere with the test composition.
Another drawback is that the test requires a full clinical study, which is costly and time consuming. It would desirable to have a method that can be used in the laboratory to screen compositions to save time and money.